Flexible driving element



Jul 8 1924.

500,458 w, R. KEEN FLEXIBLE DRIVI NG ELEMENT Filed Dec. 29, 1920 4Sheets-Sheet 1 July 8 m4.

1,500,458 w. R. KEEN FLEXI BLE DRIVING ELEMENT Filed Dec. 29 1920 4Sheets-Sheet 2 July 8 1924. 1,500,458

w. R. KEEN FLEXIBLE DRIVING ELEMENT Filed Dec. 29, 1920 4 Sheets-Sheet 5Irina-m Jufiy 8 1924.

W. R. KEEN FLEXIBLE DRIVING ELEMENT Filed Dec. 29, 1920 4 Sheets-Sheet 4Patented July 8, 19241.

teat

WALTER REUBEN KEEN, OF BIRMINGHAM, ENGLAND.

FLEXIBLE DRIVING ELEMENT.

Application filed December 29, 1820.

Serial No. 433,913.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. L.,1313.)

To all whom it may concern: 7

Be it known that LVVALTEP. REUBEN KEEN, a subject of the King of GreatBritain, residing at 87 Slade Road, Erdington, Bir' mingham, in thecounty of Warwick, England, have invented certain new and usefulImprovements in Flexible Driving Elements (for which I have filedapplications in Great Britain July 26, 1918, Serial No. 128,775,December 2 1, 1919, No. 32,275, and December 1, 1920, No. 33,858); and Ido hereby declare the following to be a full, clear, and exactdescription of the same.

This invention relates to flexible driving elements of the kind whichinclude a flexible band provided with resilient inclined grippingmembers adapted to engage with a pulley having a groove of V or othersection.

One of the objects of the present invention is to provide a generallyimproved con struction including means for preventing the grippingmembers from being permanently displaced or distorted by the forceswhich come into play when they are forced into the groove of the pulley.

The object is carried out by providing one or more transverse portionswhich extend between the resilient inclined gripping members, whichtransverse portion or portions are adapted to be distorted by inwardcomllpression upon the inclined gripping memers.

Another object of the present invention is to so construct thetransverse portion or portions which force the inclined gripping membersthat it or they provide a resilient backing for the said inclinedgripping members.

A further object of the present invention is to provide means to preventthe bodily displacement in a transverse direction of the transverseportion or portions which serve to support the inclined grippingmembers.

A further object of the present invention is to construct the transverseportion or portions with curves which mutually support each otheragainst the forces resulting from transverse compression of the inclinedgripping members.

A further object of the present invention is to provide a constructionin which an accurately pitched driving sprocket chain is combined withthe inclined resilient gripping members whereby the driving element mayrun at one end upon a driving sprocket and at the other end upon agrooved pulley.

Referring to the drawings Figure 1 is a cross sectional elevation oi oneform of driving belt constructed in accordance with this invention, thisview also showing a portion of one of the driving pulleys with which itis used.

Figure 2 is a side elevation of the same.

Figure 3 is a cross sectional elevation, Figure 4 is a longitudinalsectional elevation, and Figure 5 is a plan of a portion of a. drivingbelt made according to a modification of my invention.

Figure 6 is a cross sectional elevation, Figure 7 is a side elevation,and Figure 8 is a plan of a port-ion of a driving belt illus trating afurther modification of my invention.

Figure 9 is a cross sectional elevation, and Figure 10 is a longitudinalsectional elevation of a portion of a driving belt con structedaccording to a further modification of my invention.

Figure 11 is a perspective view of one of the clip parts of thearrangement illustrated in Figures 9 and 10.

Figure 12 is an end elevation, and Figure 13 is a sectional sideelevation of a por tion of a driving chain constructed in ac cordancewith this invention.

Figure 14: is a cross sectional elevation, and Figure 15 is a sideelevation of a portion of a driving belt illustrating a furthermodification of my invention, and

Figure 16 is a plan of the sheet steel blank for forming a section ofthe driving belt illustrated by Figures 14 and 15.

Figure 17 is a side elevation of a portion of a driving beltillustrating a further modification of my invention, and Figure 18 is aplan of the same.

Figure 19 is an end elevation of a further modification of my invention,and

Figure 20 is a cross sectional elevation of a portion of a driving beltconstructed according to a further modification of my invention andshowing also in cross section a portion of one of the driving pulleys ofthe same.

Figure 21 is a cross sectional elevation of one form of driving belt ordriving chain constructed in accordance with this invention.

Figure 22 is a side elevation of same. Figure 23 is a cross sectionalelevation and Figure 24 is a side elevation of a portion of a drivingbelt or chain made according to a modification of my invention.

Figure 25 is a cross sectional elevation and Figure 26 is a sideelevation 01": a portion of a driving belt or chain illustrating afurther modification of my invention.

Figure 2'? is a cross sectional elevation and Figure 28 is a plan of aportion of a driving beltor chain constructed according to a furthermodification of my invention.

Figure 29 is a cross sectional elevation, Figure 30 is a side elevationand Figure 31 is a plan of a portion of a driving belt or chainconstructed in accordance with this invention and illustrating a furthermodification of my invention.

Figure 32 is a view in cross section showing a further modification.

Figure 33 is a side view corresponding to Figure 32.

Figure 34 is a cross section showing a further modification.

Figure 35 is a side elevation corresponding with Figure 34.

Figure 36 is a cross section showing a further modification.

Figure 37 is a fragmentary plan view corresponding with'Figure 36.

Figure 38 is a view in cross section showing a further modification.

Figure 39 is a side view corresponding to Figure 38.

Figure 40 is a plan view of the construction shown in Figure 38.

Figure 41 is a sectional view showing a further modification".

Figure 42 is a corresponding side elevation.

Figure 43 is a plan view corresponding to Figure 42.

Figures 44, 45 and 46 are views in section, side elevation and planrespectively of a further modification.

Figures 4?, 48 and 49 are views in section, side elei ation and planrespectively of a further modification.

Figures 50, 51 and 52 are views in section, side elevation and planrespectively of a further modification. 7

Figures 53 54 and 55 are views in. sec 7 7 tion, side elevation and planrespectively of a furthere modification.

Figures 56, 57 and 58 are views in section, side elevation and planrespectively of a further modification.

Figure 59 is a view in cross section showing a further modification.

Figure 60 is a view in cross section showing a further modification.

Figure 61 is a view in section showing a further modification.

Figure 62 is a view in section showng a further modification.

Figure 63 is a View in section showing a further modification.

Figure 64 is a view in section showing a further modificatioin In thearrangement of my invention illustrated by Figures 1 and 2 a flexiblethin sheet metal or other suitable metal driving band 1 is employed madeof one thickness or laminated, that is made of two ormore thicknessesfixed together. Riveted or otherwise fixed to that side of this band 1which is next to the pulleys are the inclined sided metal wedge shapedgripping members A each of which is formed of an elongated sheet steelor other suitable sheet metal blank which is bent so as to form a fiator curved base 2 which is riveted or otherwise fixed to the driving band1 and at the two sides 3, 4 of this, the two portions of the blank arebent so that they are in planes which form acute angles with the base soas to form, the two inclined sides of the gripping member which bearagainst the pulley flanges 5 and the end portions of these parts 3, 4are bent towards one another and curved inwardly at 6, 7 so as to touchone another (see Figure 1) when pressed into the pulley, groove and thusre.- sist the lateral inward pressure of the pulley sides. Thus thesides 3, 4 form springs which are to a certain extent resilient asaforesaid and. afiord a perfect grip on the pulleys and are strengthenedbytheir ends being curved to bear against one an other as aforesaid.

' These wedge like spring gripping members A made with inWardlyeurve-dends as aforesaid are fixed to the band 1 close or nearly close together(see Figure 2) and their adjacent edges are inclined from each othersutficiently to allow of the band 1 bending properly round the smallestsize pulley with which the band is intended to be used.

Instead of the gripping members A being a secured to the inside of theband" 1 by riveting, they may be secured thereto by any other suitablemeans such for instance as by each-member A being provided with tongues8 (see Figures 3, 4 and 5) which are'pierced and raised from the basepart 2 and pass through holes in the band 1 and are closed over on theother, that is the outer, side of the same. Or as shown in Figures 6, 7and 8 the tongue like clips 9 may bepierced and raised out of the springside portions 3, 4 and be raised and closed over the sides of the band 1so as to grip the same between the base 2 and these tongues 9. Or asshown in Figures 9, 10 and lleach member A may be secured to the band byan independent clip which is made of a plate 11 adapted to fit againstthe inside'of the base part 2 and made with upstanding tongues 12 whichpass through holes in the band and are clenched over on the upper sideof the same as shown in Figure 10. Or any other convenient means may beemployed for securing the spring gripping members A to the band.

It is to be understood that the band, instead of being a thin flexiblemetal driving band, may be formed of leather or balata or cotton orother suitable material or it may be a stranded wire band orunstretchable cord with the gripping members secured thereto in anysuitable manner.

As a further modification instead of employing a driving band to carrythe resilient inclined sided gripping members A constructed with theincurved ends 6, 7 as aforesaid I may as shown for instance in Figures12 and 13 employ a driving chain preferably formed of fiat links 14jointed together by well known pin and eye connection at their ends 15or jointed together in any other suitable manner and each link 14 beingof theproper size and carrying one of the gripping members A which issecured thereto by riveting or by other suitable means, the joints ofthe chain between two links thus being between two gripping members.

Or, as a further modification, (see Figures 14, 15 and 16) the grippingmembers A may be made in a piece with the steel or other metal band, inthis case marked 15, which will be made in comparatively short lengths(or they may be made in long lengths) and when in short lengths thesewill be hinge jointed or otherwise connected together as at 16 eachlength 15 being formed of a sheet steel or other suitable sheet metalblank (see Figure 16) having inclined laterally projecting tongues 17 ateach side corresponding with the required gripping members and theseprojections 17 are then raised and bent towards one another making anacute angle with the sides of the central portion 15 which forms theband and the ends 6, 7 of the tongues are bent and curved inwardly so asto bear against one another or so as to almost touch one another, andthus the two opposed tongues constitute one of the inclined spring sidedgripping members, the adjacent edges 18 of the tongues being inclined asshown so as to permit of the band bending round the smallest size pulleywith which it is intended to be used.

Or as a further modification (see Figures 17 and 18) the base part ofeach of the gripping members A may have at the front a hooked projectingportion 20 and a corresponding hooked projection 22 at the back formedintegral with the base or fixed thereto the end 20 of one grippingmember being adaptedto engage with the corresponding hooked portion 22of the next gripping member and thus the required member or members willform a combined hook jointed driving chain and wedge shaped grippingmember.

If desired, in order to increase the frictional grip on the flanges ofthe spring sided wedge shaped gripping members A on the pulleys, theinclined faces 3, 4 of each gripping member A may have fixed to it oneor more pads of leather, india rubber or other suitable material suchfor instance as the pad 21 illustrated in Figures 12 and 13.

Moreover if desired in order to stiffen the spring sides 3, 4 of thegripping members A each gripping member can have between its sides anadditional spring or springs such as a leaf spring 28 in Figure 19 madewith a base part and two arms 23, 24, the base being fixed to theunderside of the base 2 of the gripping member A and the two arms 23, 24of the leaf spring being bent outwardly and downwardly to bear againstthe inner surfaces of the inclined sides 3, 4. Or for the same purpose acoiled wire spring may be arranged between the inclined sides 3, 4 so asto assist in springing them out wardly.

Moreover as a further modification the pulleys on to which the belt orchain formed with the said gripping members A drives may, instead ofbeing each made with a single inclined sided groove for the grippingmembers to engage with, as is usual and as shown in Figure 1, saidpulleys may have on the bottom of each groove an up wardly projectinginclined sided rib 30 (see Figure 20) thus forming an approximate Vgroove which has two small V grooves at the bottom of it so that itresembles the letter W and this rib 30 when the band is at work projectsup between the central divisions of the under sides of the grippingmembers where the said sides meet (see F igure 20) and thus the inclinedsided central rib 30 forms two additional gripping surfaces which tendsto force the sides 3, 4 of the gripping members against the inclinedsides of the flanges 5 of the pulley thus increasing the grip.

In the construction illustrated by Figures 21 and 22 a sprocket chainformed in the manner which is well understood and consisting of metallinks 35, 35, roller 38 and joint pins 37, has secured to its outsidelinks 36, 36 by the joint pins 37 the inclined sided metal wedge shapedgripping members A and B, each of which is formed of an elongated sheetsteel or other suitable sheet metal blank which blanks are bent so as toform flat surfaces 33, 34 to seat against the side links 36. The sides39, 40 of these blanks are bent or cranked so as to slope outwardly andare then bent inwardly towards one another and the end portions are bentand curved inwardly at 31, 32 so as to touch one another (see Figure 21)when pressed into the pulley groove and thus resist the lateral inwardpressure of the pulley sides.

Thus the members A, B form a wedge shaped section and being formed ashereinbefore described the sides 39, 40 form springs which are to acertain extent resilient and afford a perfect grip on the pulleys andare strengthened by their ends being curved to bear against one another.

These wedge like gripping members A, B are fixed to the opposite sideplates of the alternate links of the chain belt (see Figure 22) andtheir adjacent edges 50, 51 are either parallel to each other orconverge but a suflicient clearance or space between their extreme edgesis allowed so that the chain belt can run properly when passing betweenthe driver and the driven element. The gripping members being above thatpart of the chain belt which engages with the sprocket wheel, allow theteeth of the sprocket wheel to engage with the rollers of. the sprocketchain satisfactorily. The grooved pulley with which it is intended touse the chain belt has the groove which engages the gripping members A,B sufliciently deep to give proper clearance at the bottom of the groovewhen the said gripping members are in driving contact with the pulleyflanges.

Instead of the gripping members A, B being secured to the chain belt byriveting they may be secured to the side plates of the chain belt byother suitable means such as by making the joint pins of the chain beltwith screwed ends and securing the gripping members by nuts, or boltsand nuts could be used as joint pins and for securing the said grippingmembers to the chain belt, or any other convenient means may be employedfor securing the grippers to the chain belt.

It is to be understood that it is only neces sary to use an accuratelypitched chain belt when it is desired to transmit power by a pair ofsprockets or by a sprocket wheel and pulley, as when the chain belt isonly required for a friction drive the construction may be modified, forinstance, the rollers 38 would not be required and a seamless or otherlike oval steel ferrule could be substituted for the side plates orlinks 35, 35, the band being of sufficient width to fill the spacebetween the outer plates or links 36, 36.

As a modification the gripping members A,'B, may be made so that theirhorizontal centre line coincides or nearly coincides with the centreline of the chain belt, that is the gripping faces or sides 39, 40 ofthe gripping members A, B are level with the chain belt 36, 35 (seeFigures 23 and 21-). The gripping members A, B are formed of blanksshaped differently from those illustrated in Figure 21 and are made outof sheet steel or other suitablemetal of. an elongated form with theoppositesides inclined towards each other and flat parts O which are notquite central with the blanks. The said inclined sides have projected.portions: etl, ll so as to leave suflicient metal around the rivets 37,and also around the holes in the sides of the said grippers. A, B at 39,it), the said holes being for the purpose of inserting the rivets and toallow of same: being riveted over by a suitable punch. to secure thegrippers in position. The gripping members have flat sides 33, 3st whichproject above and extend below the side plates of the chain belt. Thepartof each gripping member which projects above the top edge of theside plate is. of sufficient length to allow of same being bent over inan outward direction from the chain belt side plate to form the flat top40, then bent downward and inclined inwardly so that \the ends touch ornearly touch one another. or the ends 31, 32 of the downwardly inclinedpart of the gripping members A, B may be bent inwardly and curledupwards as illustrated so as to touch or nearly touch the flat sides 33,3A or the said gripping member, or they may be curled downwardly so asto touch or nearly touch the lower ends of the liat sides 33, 34: ofsaid gripping memhers A, B. These gripping members may be fixed to theopposite side plates of the alternate links of the chain belt byriveting. or in any other suitable manner as aforesaid, and havetheiradjacent sides inclined from each other sufficiently to allow ofthe chain belt making the necessary angular move ment when passing roundthe smallest size sprocket or pulleywith which it is intended to beused, and they conformin their transverse section to the section of th'eV or like 7 grooved pulley element of: the transmission: 7 The grippersmay be made. integral with the side; links of the chain.

As a further modification (see Figures r 26, 27 and 28) the grippingmembers with sides A, B may be made in onepiece,.and the side plates 36,36 of the chain belt made of a shapedifferent from those hereinb eforedescribed and have their top and bottom edges extended a suitabledistance to allow of the said gripping members being secured to same attheir top face 40 and to form a bearing for the curled ends31, 32 ofsaid grippers. The blanks to form the gripping members as illustrated byFigures 25, 26, 27 and 28 are formed from sheet metal having a parallelcentral part which forms the top 40 and two side portions which areinclined towards one another. The end. portions of those parts A, B arebent towards the side plates 36fand inwardly curved at 31, 32 so as totouclrthe sideplatesBG. (see Figure 25) when pressed into the pulleygroove and thus resist the lateral inward pressure of the pulley flangesor sides. Thus the sides A, 13 form springs which are to a certainextent resilient as aforesaid. To secure the grippers (see Figures 25and 26) to the chain belt, elongated holes 42 are pierced in the top ofthe gripping members through which holes 42 projections 41 on the sideplates 36 project a suflicient distance to allow of their being rivetedover and thus secure the grippers to the chain belt.

As an alternative method of securing the gripping members A, B to theside plates (see Figures 2% and 28) projections 45, left on the sideplates 36, instead of being riveted over may be made of a suitable shapeand have holes punched or drilled to receive pins 46 which secure thegripping members to the side plates. The said pins have one side oftheir heads flattened and the ends split so that after assembling theparts together the said ends are opened and thus prevent the pins 46from falling or arring out of position.

Figures 29, 30 and 31 illustrate another application of my invention.Figure 29 is a cross sectional elevation. Figure 30 is a side elevationand Figure 31 is a plan of a portion of a chain belt illustrating adifferent method of construction from those hereinbefore describedparticularly on reference to the construction of the gripping members A,B and the side plates 36 to obtain a similar resilient action to thathereinbefore described.

The gripping members A, B are formed from sheet metal blanks with aparallel sided portion forming the top and an inclined sided portionforming the sides 46 and ends 31, 32. The blanks are bent at or near thepoint of intersection of the parallel sides and the inclined sides andinclined inwardly. The ends 31, 32 are bent inwardly and curved to touchthe outwardly curved end of the side plate 36, said gripping mem bershaving suitable rivet holes punched or drilled in the flat tops 33, 34to secure same by riveting or other suitable means to the side plates36of the chain belt. The side a plates (see Figure 29) are made in adifierent form from those herein previously described and are blanksstamped or pressed out of suitable sheet metal and of a suitable shapeto allow of the top edge beingibent outwardly to form a flange toreceive the I gripping member, said flange having holes provided toregister with the holes in the gripping member and so allow of theinsertion of rivets 43, 44,'bolts or other suitable fastening, Thebottom .ends of the side plates 36, 36 are curved outwardly at 39 so asto touch and form a seating for the ends 31, 32of the gripping membersA, B. Rivet holes are provided'at suitable centres in the flat sides ofsaid side plates 36 to receive the rivets 37 or joint pins of the chainbelt. Thus the sides 45 46 form springs which are to a certain extentresilient as aforesaid and afford a perfect grip on the pulleys and arestrengthened by the ends of the side plates being curved to form abearing for the ends of the gripping members. Moreover, if desired inorder to increase the frictional grip on the pulley flanges pads ofleather, india rubber, or other suitable frictional material may besecured to the sides of the gripping members.

In the construction shown in Figures 32 and 33 an ordinary pitch chain50 is pro vided with a member 51 and with inclined side links 52. Theside links 52 are secured to the chain 50 by the ordinary rivets of thechain and each side link is bent outwardly as shown at 53 and inwardlyas shown at 54 so that its end abuts against the part 51.

In the construction shown in Figures 34 and 35 each pair of converginggrippers 55 are made in one piece. In these figures the grippers areshown as attached to a flat link 56 of a chain or flexible band but thegrippers might equally well be applied to the link of a pitch chain ofthe roller, silent or other type. Those parts of the grippers 55 whichare adjacent to the link 56 are provided with grooves or curves orcorrugations as shown at 57 and the ends 58 abut, against a plate 59secured to the link 56 by rivets 60. The plate 59 is provided with aprojection 61 at its centre for the purpose of receiving the ends 58 ofthe grippers 55. What may be termed the apex of the gripper 55 may becorrugated with one or a plurality of curves as shown at 62 or inb steadof the curves 62 being provided this part of the gripper may be made asshown in dotted lines in Figure 34.

In the construction shown in Figures 36 and 37 a combined pitch chainand belt is shown suitable for engagement with a pulley having more thanone groove. The chain 63 may be of any suitable type and is providedwith grippers 64 having inclined sides and being provided with atransverse per- EEO tion 65 which is curved as shown at the 1 centre ofFigure 36 or which may be hinged as shown at 66 at the two end portionsof Figure 36. If required portions of the grippers 65 may be hinged asindicated in dotted lines at 67 in Figure 36.

In the construction shown in Figures 38,

39 and 40 the grippers 68 are provided with Qwith the rivets 71 thegripper is slotted so a l w it? g PPe t e an nwa d I Q of grippersareattached to the chain at a movement with respect to the rivets 71. Theends 73 of the gripper abut against each other so that the inclinedsides are provided with a resilient backing. If required the corrugatedportions 69 ma be dispensed with and this portion ma e as shown 1ndotted lines in Figure 38.

In the construction shown in Figures 41 and 42 the grippers 74 may haveabutting ends 75 or the two sides 74 may be made in one piece as shownin dotted lines at 7 6. That portion of the gripper 74 which is adjacentthe chain or belt 77 is made integral with or secured to a pressureplate 7:8. The ends of these pressure plates 78 are turned downwardly asshown at 79 in Figure 42 and serve to tend to straighten the chain orbelt after it leaves a pulley. The pressure plates 78 have a secondfunction. When the driving element commences to pass around a pulley orsprocket, especially if the pulley or sprocket is a small one, as thedriving element takes up the curvature of the pulley or sprocket theleading end 7 9 of each pressure plate 78 is displaced in relation tothe link with which it is associated. This displacement of the pressureplates78 forces a projecting portion 95 between the ends 96 of thegrippers 74 and serves to expand the grippers, i. e. move them or tendto move them apart so as to form a good driving engagement with thesides of the pulley groove. In order to provide for this lateralmovement of the grippers 74 they may be attached to the belt or chain 77by rivets 97 having enlarged portions 98 which pass through elongatedslots 99 in the grippers. Spring washers 100 may be provided between theheads of the pins 97 and the interior surfaces of the grippers 74 so asto permit of the inward movement of the pressure plates 78' togetherwith the grippers 74. The centre parts of the grippers 74 at each endmay be cut away to accommodate the ends 79 of the pressure plates 78.

If required the expansion of the grippers when the driving element'isflexed may be obtained by providing extensions upon the grippers anddispensing with the'pressure plates. In such an arrangement theextensions on the grippers engage with the underside of the next link ofthe chain or belt in the same manner that the ends 79 of the pressureplates 78 engage with t'llfl links.

In the construction shown in Figures 44,

and 46 the chain 101 is made up of cranked links as shown clearly inFigure 46 and the grippers 102 are secured to angle 7 plates 103 carriedby the Side links of the chain. Formedintegral-with the chain 101 orformed separately are plates 104 having inclined ends 105, which serveas. a resilient.

backing for the grippers 10.2. In this arrangement it. should be knownthat. each P8411" single pivoting point 106 thus allowing the grippersto oscillate upon the chain if required. This arrangement could equallywell be used with a belt or with a chain hav' ing fiat links. In thisarrangement the ends of the grippers are bent to a plurality of iency.

In the construction shown in Figures 47, v

48 and 49 the grippers 108 are made in one piece and secured to theunderside of a chain composed of flat links by engaging over rods 109.In order to keep the grippers in place ears 110 are pressed out of thegrippers and loosely engage with the rods 109. These grippers caneasily. be removed from the belt or chain by taking out the rods 109.This arrangement has the advantage that a certain limited bodily lateralmovement is permitted to the grippers. This lateral movement isparticularly useful when the driving element is running upon belts whichare not accurately in alignment. As will be seen from Figure 47 theouter part of the grippers is bent toaplurality of curves as shown at111 giving resiliency between the outer parts of the grippers aswell asthe resiliency obtained by the curved ends 112 at the inner parts of thegrippers.

A similar form of the driving element is shown in Figure 63 whereinhowever, the ears 110 are dispensed with and distance tubes 113 areplaced over the rods 109. Further, in this arrangement the bodilylateral movement of the gripper is restrained by a shoulder pin 114carried by. the 7 belt or chain and engaging in a slot 115 in thegripper. 7

In the construction shown in Fignres 50, 51 and 52 the arrangement shownis eX- tremely similar to thatshown in Figures 47 48 and 49 but thechain is here provided with integral lugs 116 to accommodate the rods109. V

In the arrangement shownin Figures 53, 54 and instead of using the lugs116 for accommodating the pins 109 a special holder 120 is provided uponthe underside of each link, which holder carries the pins .109.

lVith regard to the arrangement shown in Figures 50, 51, 52, 53, 54 and55 it will be understood that the modifications described thereto. V Inthe construction .ourves 107 producing the necessary resilllO describedin Figures 56, 5,7 and 58; the outer side linksxlfljt a roller chain aremade of angle section and Y serve to carrythe grippers 122. In Figure 71 56 the grippers are shown. hinged together at l23 but alternativelythey might 'be'made intone piece as indicated i do ed li ies rat 7 124,h l ks l2 a he l @ii are provided wi h in l ned. inflecti ns 1.2

which m resilisil beeking tor thaei ds': m

. 27 of the grippers. f i I In the construction shown in Figure 59 theinclined sided grippers 80 at the portions remote from the chain or belt81 may either be corrugated as is shown in similar parts of the otherfigures of the drawings, or the ends 82 may abut as shown. The sides 80are provided with inwardly curved portions 83' which enable the upperparts of the sides 80 to move inwardly as well as the lower parts.

In the construction shown in Figure 60 the chain or belt 84 is providedwith a carrier 85 which carries the inclined sided gripping members 86which are slidably mounted therein. The inclined sided grip ping members86 may be resiliently supported by coiled or other springs such as 87Instead of being slidably mounted in the plates 85 the gripping membersmay be secured at their upper ends to the chain or belt 84 and theirlower ends may be free and abut against the carrier 85.

It will be understood that in any of the constructions herein describedthe inclined sides of the gripping members instead of being fiat may beslightly convex to give additional resilience.

In the construction shown in Figure 61 the chain or belt 88 is providedwith inclined sided gripping members 89 which are provided with aresilient backing by a spring .90 which passes through slots or holes at91 near the ends or near the centre of the gripping members 89.

. and the gripping members 92 in addition to being provided with acurved resilient backing 93 of the kind already described may beprovided with internal springs 94 carried by the chain or belt. The ends95 of the grippers 92 are left free so that they can move together orapart under the influence of the springs 94 of the sides of the pulley.

In the construction shown in Figure 64 the larger part of the inclinedgrippers 128 is shown remote from a sprocket chain 129 whereby at oneend the driving element may run upon a chain sprocket and at the otherend may run upon a grooved pulley. The construction shown in Figure 64incorporates a number of features which have already been described withreference to the other figures and which will be readily understood.

It required pads of resilient material, springs or spring washers may beinserted between the gripping plates and the side links or between theside links and distance pieces on the joint pins.

What I claim then is 1- 1. A flexible driving element comprising aseries of links; hinges uniting said links together, end to end, to forma flexible band; an inclined sided gripping member attached to each ofsaid links adapted to engage frictionally with the sides of a pulleygroove, said gripping members having portions extending transversely inthe space between them, which portions are bent to a curve to make themresilient and operate to form a resilient backing for the inclined sidesto resist the inward displacement of said sides.

2. A flexible driving element comprising a flexible band having a seriesof inclined sided gripping members adapted to engage frictionally withthe sides of a pulley groove, said gripping members having inwardly bentportions to make them resilient said portions extending transversely inthe space between them, which portions are bent to a curve to make themresilient and operate to form a resilient backing for the inclined sidesto resist the inward disp1acement of said sides.

3. A flexible driving element comprising a flexible band havingprojections on one side, longitudinal rods carried by said projections,inclined sided gripping members mounted on said rods so as to be capableof bodily transverse movement in relation to the band and adapted toengage frictionally with the sides of a pulley groove, said grippingmembers having portions extending transversely in the space betweenthem, which portions are bent to a curve to make them resilient andoperate to form a resilient backing for the inclined sides to resist theinward displacement of said sides.

In witness whereof I affix my signature.

WALTER REUBEN KEEN.

